From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: david@fromorbit.com, darrick.wong@oracle.com
Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org,
linux-cifs@vger.kernel.org, Amir Goldstein <amir73il@gmail.com>,
linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-mm@kvack.org, linux-btrfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com
Subject: [PATCH 16/28] vfs: enable remap callers that can handle short operations
Date: Sun, 21 Oct 2018 09:16:55 -0700 [thread overview]
Message-ID: <154013861584.29026.5158930020192209258.stgit@magnolia> (raw)
In-Reply-To: <154013850285.29026.16168387526580596209.stgit@magnolia>
From: Darrick J. Wong <darrick.wong@oracle.com>
Plumb in a remap flag that enables the filesystem remap handler to
shorten remapping requests for callers that can handle it. Now
copy_file_range can report partial success (in case we run up against
alignment problems, resource limits, etc.).
We also enable CAN_SHORTEN for fideduperange to maintain existing
userspace-visible behavior where xfs/btrfs shorten the dedupe range to
avoid stale post-eof data exposure.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
---
Documentation/filesystems/vfs.txt | 4 +++-
fs/read_write.c | 28 ++++++++++++++++++++--------
include/linux/fs.h | 5 +++--
mm/filemap.c | 11 +++++++----
4 files changed, 33 insertions(+), 15 deletions(-)
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 1bd2919deaca..5f71a252e2e0 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -970,7 +970,9 @@ otherwise noted.
negative error code if errors occurred before any bytes were remapped.
The remap_flags parameter accepts REMAP_FILE_* flags. If
REMAP_FILE_DEDUP is set then the implementation must only remap if the
- requested file ranges have identical contents.
+ requested file ranges have identical contents. If REMAP_CAN_SHORTEN is
+ set, the caller is ok with the implementation shortening the request
+ length to satisfy alignment or EOF requirements (or any other reason).
fadvise: possibly called by the fadvise64() system call.
diff --git a/fs/read_write.c b/fs/read_write.c
index ea30666013b0..c0bcc1a20650 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1593,7 +1593,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
cloned = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
- min_t(loff_t, MAX_RW_COUNT, len), 0);
+ min_t(loff_t, MAX_RW_COUNT, len),
+ REMAP_FILE_CAN_SHORTEN);
if (cloned > 0) {
ret = cloned;
goto done;
@@ -1721,6 +1722,8 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
* can't meaningfully compare post-EOF contents.
*
* For clone we only link a partial EOF block above the destination file's EOF.
+ *
+ * Shorten the request if possible.
*/
static int generic_remap_check_len(struct inode *inode_in,
struct inode *inode_out,
@@ -1729,16 +1732,24 @@ static int generic_remap_check_len(struct inode *inode_in,
unsigned int remap_flags)
{
u64 blkmask = i_blocksize(inode_in) - 1;
+ loff_t new_len = *len;
if ((*len & blkmask) == 0)
return 0;
- if (remap_flags & REMAP_FILE_DEDUP)
- *len &= ~blkmask;
- else if (pos_out + *len < i_size_read(inode_out))
- return -EINVAL;
+ if ((remap_flags & REMAP_FILE_DEDUP) ||
+ pos_out + *len < i_size_read(inode_out))
+ new_len &= ~blkmask;
- return 0;
+ if (new_len == *len)
+ return 0;
+
+ if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
+ *len = new_len;
+ return 0;
+ }
+
+ return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
}
/*
@@ -2014,7 +2025,8 @@ loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
{
loff_t ret;
- WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP));
+ WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
+ REMAP_FILE_CAN_SHORTEN));
ret = mnt_want_write_file(dst_file);
if (ret)
@@ -2115,7 +2127,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
deduped = vfs_dedupe_file_range_one(file, off, dst_file,
info->dest_offset, len,
- 0);
+ REMAP_FILE_CAN_SHORTEN);
if (deduped == -EBADE)
info->status = FILE_DEDUPE_RANGE_DIFFERS;
else if (deduped < 0)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 544ab5083b48..34c22d695011 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1727,8 +1727,10 @@ struct block_device_operations;
* See Documentation/filesystems/vfs.txt for more details about this call.
*
* REMAP_FILE_DEDUP: only remap if contents identical (i.e. deduplicate)
+ * REMAP_FILE_CAN_SHORTEN: caller can handle a shortened request
*/
#define REMAP_FILE_DEDUP (1 << 0)
+#define REMAP_FILE_CAN_SHORTEN (1 << 1)
/*
* These flags signal that the caller is ok with altering various aspects of
@@ -1736,9 +1738,8 @@ struct block_device_operations;
* implementation; the vfs remap helper functions can take advantage of them.
* Flags in this category exist to preserve the quirky behavior of the hoisted
* btrfs clone/dedupe ioctls.
- * There are no flags yet, but subsequent commits will add some.
*/
-#define REMAP_FILE_ADVISORY (0)
+#define REMAP_FILE_ADVISORY (REMAP_FILE_CAN_SHORTEN)
struct iov_iter;
diff --git a/mm/filemap.c b/mm/filemap.c
index e9091d731f84..1775d4ad3317 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3045,8 +3045,7 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
bcount = ALIGN(size_in, bs) - pos_in;
} else {
if (!IS_ALIGNED(count, bs))
- return -EINVAL;
-
+ count = ALIGN_DOWN(count, bs);
bcount = count;
}
@@ -3056,10 +3055,14 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in,
pos_out < pos_in + bcount)
return -EINVAL;
- /* For now we don't support changing the length. */
- if (*req_count != count)
+ /*
+ * We shortened the request but the caller can't deal with that, so
+ * bounce the request back to userspace.
+ */
+ if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
return -EINVAL;
+ *req_count = count;
return 0;
}
next prev parent reply other threads:[~2018-10-21 16:16 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-21 16:15 [PATCH v6 00/28] fs: fixes for serious clone/dedupe problems Darrick J. Wong
2018-10-21 16:15 ` [PATCH 01/28] vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOF Darrick J. Wong
2018-10-21 16:15 ` [PATCH 02/28] vfs: check file ranges before cloning files Darrick J. Wong
2018-10-21 16:15 ` [PATCH 03/28] vfs: exit early from zero length remap operations Darrick J. Wong
2018-10-21 16:15 ` [PATCH 04/28] vfs: strengthen checking of file range inputs to generic_remap_checks Darrick J. Wong
2018-10-21 16:15 ` [PATCH 05/28] vfs: avoid problematic remapping requests into partial EOF block Darrick J. Wong
2018-10-21 16:15 ` [PATCH 06/28] vfs: skip zero-length dedupe requests Darrick J. Wong
2018-10-21 16:15 ` [PATCH 07/28] vfs: rename vfs_clone_file_prep to be more descriptive Darrick J. Wong
2018-10-21 16:15 ` [PATCH 08/28] vfs: rename clone_verify_area to remap_verify_area Darrick J. Wong
2018-10-21 16:16 ` [PATCH 09/28] vfs: combine the clone and dedupe into a single remap_file_range Darrick J. Wong
2018-10-21 16:16 ` [PATCH 10/28] vfs: pass remap flags to generic_remap_file_range_prep Darrick J. Wong
2018-10-21 16:16 ` [PATCH 11/28] vfs: pass remap flags to generic_remap_checks Darrick J. Wong
2018-10-21 16:16 ` [PATCH 12/28] vfs: remap helper should update destination inode metadata Darrick J. Wong
2018-10-21 16:16 ` [PATCH 13/28] vfs: make remap_file_range functions take and return bytes completed Darrick J. Wong
2018-10-21 16:16 ` [PATCH 14/28] vfs: plumb remap flags through the vfs clone functions Darrick J. Wong
2018-10-21 16:16 ` [PATCH 15/28] vfs: plumb remap flags through the vfs dedupe functions Darrick J. Wong
2018-10-21 16:16 ` Darrick J. Wong [this message]
2018-10-21 16:17 ` [PATCH 17/28] vfs: hide file range comparison function Darrick J. Wong
2018-10-21 16:17 ` [PATCH 18/28] vfs: clean up generic_remap_file_range_prep return value Darrick J. Wong
2018-10-21 16:17 ` [PATCH 19/28] ocfs2: truncate page cache for clone destination file before remapping Darrick J. Wong
2018-10-21 16:17 ` [PATCH 20/28] ocfs2: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-21 16:17 ` [PATCH 21/28] ocfs2: support partial clone range and dedupe range Darrick J. Wong
2018-10-21 16:17 ` [PATCH 22/28] ocfs2: remove ocfs2_reflink_remap_range Darrick J. Wong
2018-10-21 16:17 ` [PATCH 23/28] xfs: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-21 16:17 ` [PATCH 24/28] xfs: clean up xfs_reflink_remap_blocks call site Darrick J. Wong
2018-10-22 2:11 ` Dave Chinner
2018-10-21 16:17 ` [PATCH 25/28] xfs: support returning partial reflink results Darrick J. Wong
2018-10-22 2:14 ` Dave Chinner
2018-10-21 16:18 ` [PATCH 26/28] xfs: remove redundant remap partial EOF block checks Darrick J. Wong
2018-10-21 16:18 ` [PATCH 27/28] xfs: remove xfs_reflink_remap_range Darrick J. Wong
2018-10-22 2:17 ` Dave Chinner
2018-10-21 16:18 ` [PATCH 28/28] xfs: remove [cm]time update from reflink calls Darrick J. Wong
2018-10-22 2:18 ` Dave Chinner
2018-10-22 2:21 ` [PATCH v6 00/28] fs: fixes for serious clone/dedupe problems Dave Chinner
2018-10-22 4:37 ` Dave Chinner
2018-10-22 4:52 ` Al Viro
2018-10-22 5:08 ` Dave Chinner
2018-10-22 5:42 ` Amir Goldstein
2018-10-22 6:55 ` Dave Chinner
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